feat: add Codex Apps sediment file remapping (#15197)

## Summary
- bridge Codex Apps tools that declare `_meta["openai/fileParams"]`
through the OpenAI file upload flow
- mask those file params in model-visible tool schemas so the model
provides absolute local file paths instead of raw file payload objects
- rewrite those local file path arguments client-side into
`ProvidedFilePayload`-shaped objects before the normal MCP tool call

## Details
- applies to scalar and array file params declared in
`openai/fileParams`
- Codex uploads local files directly to the backend and uses the
uploaded file metadata to build the MCP tool arguments locally
- this PR is input-only

## Verification
- `just fmt`
- `cargo test -p codex-core mcp_tool_call -- --nocapture`

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/codex-api/Cargo.toml

@@ -14,22 +14,24 @@ codex-protocol = { workspace = true }
 codex-utils-rustls-provider = { workspace = true }
 futures = { workspace = true }
 http = { workspace = true }
+reqwest = { workspace = true, features = ["json", "stream"] }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 thiserror = { workspace = true }
-tokio = { workspace = true, features = ["macros", "net", "rt", "sync", "time"] }
+tokio = { workspace = true, features = ["fs", "macros", "net", "rt", "sync", "time"] }
 tokio-tungstenite = { workspace = true }
 tungstenite = { workspace = true }
 tracing = { workspace = true }
 eventsource-stream = { workspace = true }
 regex-lite = { workspace = true }
-tokio-util = { workspace = true, features = ["codec"] }
+tokio-util = { workspace = true, features = ["codec", "io"] }
 url = { workspace = true }
 
 [dev-dependencies]
 anyhow = { workspace = true }
 assert_matches = { workspace = true }
 pretty_assertions = { workspace = true }
+tempfile = { workspace = true }
 tokio-test = { workspace = true }
 wiremock = { workspace = true }
 reqwest = { workspace = true }